Can bus issues
Discussion
Hope this is the right bit of the forum, if not could someone please move... Oh, and sorry for long post but I thought detail would help.
My 62 plate Volvo has developed major electrical gremlins. On Sunday last week having been parked at the roadside for 48 hours it wouldn't move. Loads of warnings on the dash, including parking brake failure, and the brake wouldn't release. By the time the mobile tech sent by Volvo arrived many of the warnings had cleared, with the remaining ones going when he disconnected the battery (these were for airbag and engine modules). Car then seemed fine.
Drove home on Monday (170 miles) calling in at dealer to book car for a checkup as we passed. 10 miles from home parking brake and park assist warnings came on. Pulled into layby, called dealer again to get car booked in on Tuesday, was told to drive home carefully. As I pulled out of layby dash lit up like a Christmas tree and power cut to almost stalling (almost got rear-ended as a result). Got off main road a hundred yards later and called for flatbed, with warnings for most major systems including total brake failure (brakes working fine) and power steering failure (power steering intermittent). Even radio amp cut out.
Dealer got car on Tuesday but didn't look at it until yesterday. Faults showing on nearly all systems across car, no clue as to cause but would diagnose and fix today. Only today all the faults have cleared again, nothing showing on code reader, so their current plan is to keep test driving until it faults again.
Anyone got better suggestions as to where they should start looking? Their current approach seems doomed to failure, particularly as they couldn't find the problem when the faults were showing. Presumably swapping out parts won't be simple as the problem could be anywhere on the bus?
My 62 plate Volvo has developed major electrical gremlins. On Sunday last week having been parked at the roadside for 48 hours it wouldn't move. Loads of warnings on the dash, including parking brake failure, and the brake wouldn't release. By the time the mobile tech sent by Volvo arrived many of the warnings had cleared, with the remaining ones going when he disconnected the battery (these were for airbag and engine modules). Car then seemed fine.
Drove home on Monday (170 miles) calling in at dealer to book car for a checkup as we passed. 10 miles from home parking brake and park assist warnings came on. Pulled into layby, called dealer again to get car booked in on Tuesday, was told to drive home carefully. As I pulled out of layby dash lit up like a Christmas tree and power cut to almost stalling (almost got rear-ended as a result). Got off main road a hundred yards later and called for flatbed, with warnings for most major systems including total brake failure (brakes working fine) and power steering failure (power steering intermittent). Even radio amp cut out.
Dealer got car on Tuesday but didn't look at it until yesterday. Faults showing on nearly all systems across car, no clue as to cause but would diagnose and fix today. Only today all the faults have cleared again, nothing showing on code reader, so their current plan is to keep test driving until it faults again.
Anyone got better suggestions as to where they should start looking? Their current approach seems doomed to failure, particularly as they couldn't find the problem when the faults were showing. Presumably swapping out parts won't be simple as the problem could be anywhere on the bus?
The chances are that a CAN Logger will show up many codes if as it sounds there is a problem with the power supply
I know this might sound stupid but - Is there a chance that the Battery has an internal fault and is going open cicuit for milliseconds, a good discharge test on the battery will soon show a fault like this
I would also consider driving the vehicle with 21 Watt bulbs connected from Body -ive to the main Battery +ive and ignition +ive supplies at the Main Fusebox, should the fault be related to a Fusebox supply problem you will notice a change of bulb brightness as long as they are mounted in your sight
I know this might sound stupid but - Is there a chance that the Battery has an internal fault and is going open cicuit for milliseconds, a good discharge test on the battery will soon show a fault like this
I would also consider driving the vehicle with 21 Watt bulbs connected from Body -ive to the main Battery +ive and ignition +ive supplies at the Main Fusebox, should the fault be related to a Fusebox supply problem you will notice a change of bulb brightness as long as they are mounted in your sight
The clues should all be in the DTC's that have been set, it's worth looking at Historic DTC's with this kind of issue, not just those set now. It should be possible to determin if some modules are suffering more or differently to others, which can help find a physical connection or wire damage issue on the bus(ses), identify if one or more bus is affected etc.
If there are vehicle power issues I would expect at least one, likely more, modules to set DTC's for this on a modern car.
The DTC's, Snapshot/Freeze Frame and Extended data are the best places to start, clearing these and hoping only a few will come back is only worth while if there has been physical investigation since last clear, such as the power removal clear technique used roadside...
If there are vehicle power issues I would expect at least one, likely more, modules to set DTC's for this on a modern car.
The DTC's, Snapshot/Freeze Frame and Extended data are the best places to start, clearing these and hoping only a few will come back is only worth while if there has been physical investigation since last clear, such as the power removal clear technique used roadside...
ABS and Engine management etc use more regularly transmitted data, so detect these faults faster, but on the whole, on most vehicles are robust units... it's far more likely to be a bit of harness wire damage, or a connector that isn't fully latched.
Faults should be retained in the memories of the modules for some time, unless cleared, but may change state, the description of these states can vary between OEM's, but would likely show up as Historic, or Intermittant in some way on tools, most people, and some cheap after market tools only look at Confirmed faults which are usually hard faults present now, and maybe Pending faults which will transition to Confirmed if the fault is detected again/for longer.
Faults should be retained in the memories of the modules for some time, unless cleared, but may change state, the description of these states can vary between OEM's, but would likely show up as Historic, or Intermittant in some way on tools, most people, and some cheap after market tools only look at Confirmed faults which are usually hard faults present now, and maybe Pending faults which will transition to Confirmed if the fault is detected again/for longer.
It's a V60, 2013 model with the D4 engine. Once the faults disappear there is apparently no trace of them on the code reader, they're not being recorded.
Found a report of Car and Driver having a S60 T6 on long term test that developed similar sounding symptoms when barely run in, and on that Volvo USA changed 5 modules and most of the wiring harness as they never could trace the problem.
Found a report of Car and Driver having a S60 T6 on long term test that developed similar sounding symptoms when barely run in, and on that Volvo USA changed 5 modules and most of the wiring harness as they never could trace the problem.
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